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JB Weld to fill corrosion pitting.

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JMC3
JMC3 Member Posts: 5
in Strictly Steam

I am rebuilding my old Weil Mclain steam boiler. A steam leak eroded the elastomer seal and then corrosion caused pitting of the seal face. The deepest corrosion is less than 0.02". I used JB Weld to fill the void. The repair looks great and is solid, but does anyone have experience with such restorations that you can share?

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 27,580

    Unless you got the surface down to clean metal, it won't stay put in any kind of long run.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • JMC3
    JMC3 Member Posts: 5

    The surface was well-prepared for a good bond. The repair is located directly underneath the elastomer seal, so there is no particular stress load. My concern is whether the JB Weld will hold up to thermal cycling and low pressures (<3 psi.)

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,472

    @JMC3

    I never used it on an internal boiler surface. But we serviced a ton of HB Smit CI boiler the "Mills Style" boiler. Thes boilers had sections that were connected to a CI header external to the boiler. The connections to the header were an 1 1/2" or 2" nipple (depending on the model boiler) with a locknut and an elastomer gasket. When the gasket leaked the surface on the CI header would get corroded and pitted. We used to grind them down and this worked as you could tighten the locknut to make up for the metal ground off.

    But some of them were too pitted to take off that much metal so we ground it as much as possible then used JB weld.

    It worked well.

    How long it lasted I can't really say but we had no problem getting the gaskets to seal. At the very least it will buy you a few years.

    Mad Dog_2JMC3
  • mattmia2
    mattmia2 Member Posts: 17,465

    permatex would be better because it will flex the same as the o-ring but jb weld will probably work as long as you got it down to cast iron.

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,472

    Not sure Permatex will get along with the gasket material

  • mattmia2
    mattmia2 Member Posts: 17,465
    https://forum.heatinghelp.com/discussion/comment/1898602#Comment_1898602

    a belt sander works better than a grinder because it makes it at least somewhat flat.

    https://forum.heatinghelp.com/discussion/comment/1898608#Comment_1898608

    i guess you couldn't be 100% sure without getting a bunch of engineers together but it is kind of designed to seal where 2 molded gaskets come together, it is very commonly specified for that on engines.

  • patrykrebisz
    patrykrebisz Member Posts: 137

    do you have any pics?

    »»» See my steam heat YouTube videos:
    https://www.youtube.com/@HeatingBlog

  • JMC3
    JMC3 Member Posts: 5

    All good comments, thanks. I will proceed with JB Weld Original 8265 two-part to fill in the pitting (recommended by JB technical support), sand to flush then apply a thin layer of Permatex red to seal the entire face and let cure. Then I'll assemble the sections with the elastomer seals and do a hydrostatic test before building a head of steam.

  • mattmia2
    mattmia2 Member Posts: 17,465

    filling it with something like this might help too by removing the chlorides from the water which is what the synthetic rubber compounds tend to not be compatible with so removing the chlorides may slow the hardening of the o-rings.

    https://www.supplyhouse.com/Axiom-PUROPAL-1W-Puropal-1W-H2O-Demineralizer

    JMC3
  • JMC3
    JMC3 Member Posts: 5

    @mattmia2 I used Rectorseal 8-way in this boiler since installation in '94. I had called Weil-McLain for their OK on compatibility with the elastomer seals. Other than this particular zone of leakage, the rings came out of their glands easily and still pliable, though not reusable. Thanks for your help.

  • ChrisJ
    ChrisJ Member Posts: 17,519
    https://forum.heatinghelp.com/discussion/comment/1898614#Comment_1898614

    For some reason I think their seals are EPDM, but, I have no idea why I think that and honestly wouldn't trust it without getting confirmation on it.

    But I'm not sure of many things that aren't compatible with silicone RTV. I suspect silicone rtv will not want to stick to it, but I don't think it would hurt it.

    @JMC3 is this an EG series you're fixing? I'd love to see pictures of the before / during / after.

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

  • mattmia2
    mattmia2 Member Posts: 17,465
    https://forum.heatinghelp.com/discussion/comment/1898832#Comment_1898832

    permatex has some extra chemistry that ordinary rtv does not too. it sticks pretty tenaciously to a lot of stuff that rtv wouldn't, it spreads out more than rtv, and you can clean the uncured product off with solvent.

  • JMC3
    JMC3 Member Posts: 5

    @ChrisJ Good call on the chemistry risk. Permatex Ultra Red is an oxime-cure silicone. Oxime-cure silicones are widely used around elastomeric seals because they are non-corrosive after curing and generally compatible with many rubber compounds. The attached TDS identifies the product as an oxime silicone rubber. Permatex specifically states the product is intended for use with rubber cut gaskets and is "non-corrosive." I intend to use a very thin layer of Permatex and let it cure before assembly with the elastomer seals.

    The boiler block is a P-386 (old). The water side is beautiful since I used Rectorseal 8-way and blew down regularly. I will try to document my progress with photos.

    PermatexRed_80012_tds.pdf
    ChrisJ

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